Devices for opening and closing an electric circuit in response to changes in values of fluid pressure by admitting the fluid pressure to one side of a rapid deflection actuator, such as a snap acting diaphragm, causing it to move from a first configuration to a second configuration at a predetermined actuation pressure value and return at another de-actuation pressure value are well known. Typically, a motion transfer member is movably mounted adjacent the actuator and adapted to transfer motion from the actuator to a movable arm of an electric switch.
In HVAC and industrial applications where high pressure “cutouts” for compressors are encountered (elevated temperatures and pressures on the order of 2000 psig and 125° C.), there is a need for a switch that is both robust and stable throughout the range of pressures and temperatures seen in operation for a given working fluid. Pressure switching actuators for high pressure applications to-date have been made utilizing homogeneous layers of nested disc stacks for the actuator member. These devices have, however, suffered from significant change in the pressure switch points over the temperature range of −25° C. to 125° C. seen in operation. The shift in switch pressure points with temperature can lead to early or late cutout of the compressor/system in which the switch is incorporated. There is a need for more precise mechanical switches which maintain constant switch points over a wide range of temperatures while measuring high pressure of fluids.